1. Field of the Invention
The present invention relates generally to a method of measuring the amount of movement, or displacement, of an object having a uniformly periodic structure and more particularly to a method of measuring the amount of movement of an object for use in various encoders or tracking control or seek control in optical disk systems.
2. Discussion of Background
There is known an optical measuring system for measuring a physical quantity of an object which applies light from a light source to the object and detects light reflected from or transmitted through the object with a sensor.